Diagnostic Routine D

2012 Ford Explorer AWD V6-3.5LSECTION Diagnostic Routine D



Diagnostic Routine D

Diagnostic Overview

U0129

Normal Operation and Fault Conditions

DTC Fault Trigger Conditions






Pinpoint Test

1. VERIFY THE CUSTOMER CONCERN

1. Ignition ON.

2. Verify there is an observable symptom present.

Is an observable symptom present?








2. CHECK THE COMMUNICATION NETWORK

1. Ignition ON.

2. Using a scan tool, perform a network test.

Does the ABS (Anti-Lock Brake System) module pass the network test?








3. RETRIEVE THE RECORDED DTCs (Diagnostic Trouble Codes) FROM THE ABS (Anti-Lock Brake System) AND PCM (Powertrain Control Module) SELF-TESTS

1. Check for recorded DTCs (Diagnostic Trouble Codes) from the following modules.

- ABS (Anti-Lock Brake System) module
- PCM (Powertrain Control Module)

Are any low or high voltage DTCs (Diagnostic Trouble Codes) recorded?








4. CHECK FOR DTC (Diagnostic Trouble Code) U0129 SET IN OTHER MODULES

1. Using a scan tool, clear all DTCs (Diagnostic Trouble Codes).

2. Ignition OFF.

3. Ignition ON.

4. Wait 10 seconds.

5. Using a scan tool, perform the PCM (Powertrain Control Module) KOEO (Key ON Engine OFF) self-test.

Does the PCM (Powertrain Control Module) set DTC (Diagnostic Trouble Code) U0129?







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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.